Process for plating metallic materials



United States Patent PROCESS FOR PLATING METALLIC MATERIALS HansBothmann, Iserlohn, and Erich Mohr, Nachrodt, Kl'eis Altena, Germany,assignors to Westfiilische Leichtmetallwerke G.m.b.H., Nachrodt, KreisAltena, Germany, a corporation of Germany No Drawing. Filed May 20,1955, Ser. No. 510,057

In Germany Nov. 21, 1949 Public Law 619, Aug. 23, 1954 Patent expiresNov. 21, 1969 4 Claims. (Cl. 29-4975) It is known to produce platedsemi-finished products by laying a core material and a plating materialone above the other, heating the two together and rolling out at thesame temperature. During the rolling process, the plating layer becomeswelded to the core material during the first few passes, so that duringsubsequent passes, the plated material behaves as a homogeneous materialunder the roller. When this method is used, however, considerabledifficulties are encountered as soon as attempts are made to apply aplating layer to a material which has the same or substantially the sameresistance to deformation as the core material at the rollingtemperature used. For example, while it is readily possible for arelatively hard core material to be welded fast to a softer platingmaterial in the first or second pass when using a uniform rollingtemperature, it is not possible to plate material by the rolling processif the core material has the same resistance to deformation as theplating material, that is to say if both materials have the same degreeof softness at the rolling temperature used. It is immaterial if the twomaterials have either a low or a high resistance to deformation at therolling temperature used. For example, in connection with light metals,it is readily possible for a relatively hard core material, for examplean Al-Cu-Mg alloy, to be united to form a plated material with a verysoft plating material, such as pure aluminum, by using a rolling processwith a uniform rolling temperature of 440 C. On the other hand, it isnot possible for a lightly alloyed core material, for example a lowAl-Mg-Si alloy to be plated with pure aluminum as the plating material,or for normal industrial aluminum to be plated with ultra-pure aluminum,by the rolling method. In the latter case, it is immaterial whattemperature is used for the rolling operation. The reason for thisdifferent behavior is perhaps to be found in the fact that in the firstcase, namely when using the Al-Cu-Mg alloy and a pure aluminum, thematerials have a different resistance to deformation at the sametemperature so that relative movement between the plating material andcore material takes place during the rolling. In the second case, on thecontrary, in which the Al-Mg-Si alloys and the pure aluminum, or theindustrial aluminum and the ultra-pure aluminum, have substantially thesame resistance to deformation at the same temperature, this relativemovement does not occur. Due to the friction which is set up by therelative movement, it is obvious that atomic forces are set up, so thata satisfactory welding is possible in the first case, while the weldingoperation is a failure in the second case.

Patented May 23, 1961 It has now been found that metallic materials canbe satisfactorily plated with a metallic plating material having thesame or substantially the same resistance to deformation if the corematerial and the plating material are welded to one another in acondition in which both materials have different resistances todeformation. If the core materal and plating material are rolled on toone another in such a condition, it is to be observed that the platingis satisfactory after the first few passes. Since the resistances todeformation are dependent on temperature, the differentiation in theresistances to deformation can be produced by the two materials beingrolled on to one another at different initial temperatures.

Example 1 An aluminum alloy containing 0.8 percent Mg, 08 percent Si,and 0.3 percent Mn, which is to be used as core material, is heated to atemperature in the region of 250-370 C., preferably 300-350 C. Justprior to the rolling operation, a plating material consisting of a plateof pure aluminum (98 %-99.8%) which is heated to about 400600 0,preferably 550 C., is laid on the core material and the two materialsare rolled together. A satisfactory plating is produced.

Example 2 Industrial aluminum (about 99%) to be used as a core materialis heated to about 250-375 0., preferably 300350 C. A plate ofultra-pure aluminum (aluminum content: more than 99.9%) heated to about400-650 C., preferably 550 C., is laid on the said core material and thetwo materials are jointly rolled. The two materials become completelywelded to one another at the place of contact.

We claim:

1. A process for plating metallic materials with a metallic coveringmaterial having at least substantially the same resistance todeformation, by heating and rolling, wherein the core material and theplating material are rolled in a condition in which they have differentresistances to deformation.

2. A plating process as claimed in claim 1, wherein the core andcovering materials are heated separately from one another and havedifferent temperatures during the rolling operation.

3. A plating process as claimed in claim 1, wherein a low-alloy aluminumalloy at a temperature of about 250-375 C. is plated with pure aluminumat a temperature of about 400-650 C.

4. A plating process as claimed in claim 1, wherein industrial aluminumat a temperature of about 250-375 C. is plated with ultra-pure aluminumat a temperatureof about 400-650 C.

References Cited in the file of this patent UNITED STATES PATENTSHoglund Feb. 23, 1943 Boessenkool et al July 10, 1956 OTHER REFERENCES

1. A PROCESS FOR PLATING METALLIC MATERIALS WITH A METALLIC COVERINGMATERIAL HAVING AT LEAST SUBSTANTIALLY THE SAME RESISTANCE TODEFORMATION, BY HEATING AND ROLLING, WHEREIN THE CORE MATERIAL AND THEPLATING MATERIAL ARE ROLLED IN A CONDITION IN WHICH THEY HAVE DIFFERENTRESISTANCES TO DEFORMATION.
 2. A PLATING PROCESS AS CLAIMED IN CLAIM 1,WHEREIN THE CORE AND COVERING MATERIALS ARE HEATED SEPARATELY FROM ONEANOTHER AND HAVE DIFFERENT TEMPERATURES DURING THE ROLLING OPERATION.